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Host Rock for Gold
Name: Tim
Status: Student
Grade: 4-5
Location: N/A
Country: Australia
Date: May 2007
Question:
Can gold be found in any other host rock other than quartz?
Replies:
Gold is often brought into rocks dissolved in hot magmatic waters. As
such it can be deposited in any rock that allows the passage of these
hot waters through cracks and or primary porosity. As a result you can
get what are known as disseminated gold ores where the gold is so fine
you cannot see it with the naked eye of even a low power microscope.
In other cases, gold bearing rock may be eroded and the gold
re-deposited in other rock types. Again, this may lead to a very low
grade of ore, but one that is still economically useable.
Gold can also be mixed with other metallic ores in very small amounts.
For many years, New Jersey Lead and Zinc Co., recovered the gold present
in their lead/zinc ore by scraping and refining the metallic scale in
the furnaces and retorts. The gold paid their expenses and the lead and
zinc were pure profit. As a result, they continued to refine ore even
in times of poor lead and zinc prices.
As the old saying goes, "Gold is where (and in what rock) you find it".
Bob Avakian
OSU-Okmulgee
Gold forms few, if any, chemical compounds that are stable in a geological
environment. I do not know of any, but there could be. Consequently, metallic
gold finds itself in an environment that is most plentiful and non-reactive.
Quartz fills those two conditions. I suspect that is why metallic gold is
usually found in a quartz matrix.
Vince Calder
From the famous PBS series "The Making of the Continent" (North America), it was
given that if you find "greenstone or more particularly greenschist" you are
likely to find gold or silver.
Greenstone and Greenschist can be found at the following site:
http://en.wikipedia.org/wiki/Greenstone_belt
http://en.wikipedia.org/wiki/Greenstone
http://en.wikipedia.org/wiki/Greenschist
Steve Sample
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Update: June 2012
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